Electrode structures of a secondary cell are mainly classified into two types, i.e., a spiral-wound type and a layer type. In a cell having the spiral-wound type electrode structure (a spiral-wound cell; refer to, for example, Patent Literature 1), a positive electrode and a negative electrode which are spirally wound with a separator interposed therebetween are housed in a cell case. In a cell having the layer type electrode structure (a layer cell), an electrode group including a positive electrode and a negative electrode which are alternately stacked with a separator interposed therebetween is housed in a cell case. Patent Literature 2 discloses a cylindrical-type cell in which disc-shaped electrodes are stacked. Patent Literature 3 discloses a rectangular-type cell in which rectangular sheet-shaped electrodes are stacked.